Endodontics, a specialty of the field of dentistry, relates to the diagnosis and treatment of diseases of the dental pulp tissues residing in teeth. When pulp in a tooth becomes diseased and must be treated to retain that tooth in the patient's mouth, it is necessary to enter the pulp chamber, locate each of the canals contained in the tooth's root structure, and to pass endodontic instruments, called files, through each canal to it's end point, the apical foramen (the apex). During this initial negotiation of the canal spaces and during the procedures that follow, which include the shaping, cleaning, and filling of those canals it is critical to determine the exact endpoint of these spaces so that none of the infected canal space is left untreated or that surplus filling materials are not pushed through the ends of the root canal, both outcomes being risks for failure of treatment and loss of the tooth at some later time.
When root canal therapy began as an accepted procedure, in the late 1800's, dental x-rays were used to determine the lengths of canals by placing a root canal instrument into each canal, taking an x-ray image of it in place, and then measuring the discrepancy of the file length from the end of the canal to back figure it's length. This method of length determination was the only way to accomplish this important objective until the 1960's when Sunada invented an electronic method of length determination by recognizing that root structure was relatively non-conductive whereas the tissues of the patient's jaw at the end of these apical foramina was conductive. This enabled the end point of the canal to be found by measuring currents between a ground lead on the patient's lip and a lead touching the shank of a root canal file placed to the end of the canal space. When this electronic device, essentially an ohm meter, was hook up, it would register little or no current flow while the file tip was within the root space of the tooth but would show a current flow when the file tip approached and passed the apical foramen on it's way toward the tissues surrounding the end of the canal.
This method of length determination, known as electronic apex location, is currently the most accurate and efficient way to determine the length of a root canal, because the exit points of root canals are often not visible on dental x-rays. Also, this procedure eliminates the time consuming process of capturing and developing a radiographic image in the middle of treatment. However, there are several challenges associated with current apex locator designs and the ability to effectively prepare and use these devices in the operative environment.
The greatest challenge is the management of the electronic leads necessary in its operation. These leads must be autoclaved between patients to prevent cross-contamination from infectious products, they must be kept off of contaminated surfaces in the dental operatory, and they must be kept untangled from the many other cords and cables in the operative site. Furthermore, it is necessary to shield the apex locator in barrier material as it cannot be autoclaved like the lead set. Currently no apex locator is designed to facilitate autoclaving of leads and wrapping of the electronic control unit in a simple, efficient manner.
A second challenge is positioning of apex locator display in the operatory as counter space is limited, each dentist has a different operatory configuration, and the display must be easily seen by the dentist during initial instrumentation procedures.
The device described herein resolves each of these issues in a simple, cost effective, and procedurally ideal manner.